Lubricant compositions

ABSTRACT

Lubricant compositions comprises a lubricant base oil and one or more compounds resulting the modification of a succinimide represented by formula (1) or (2)  
                 
 
     wherein R 1  and R 2  may be the same or different and are each independently a hydrocarbon group having 8 to 30 carbon atoms, R 3  and R 4  may be the same or different and are each independently a hydrocarbon group having 1 to 4 carbon atoms, R 5  is hydrogen or a hydrocarbon group having 1 to 30 carbon atoms, n is an integer from 1 to 7. The lubricant compositions have a long-lasting anti-shudder property, an enhanced transmission capacity for a wet clutch, and an excellent shifting property.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to lubricant compositions, and moreparticularly to lubricant compositions which are not decreased inanti-shudder property over an extended period of time and have anenhanced transmission torque capacity for wet clutches and/or wetbrakes, suitable for automatic transmissions and continuously variabletransmissions.

[0003] 2. Description of the Prior Art

[0004] Most of the automatic transmissions and continuously variabletransmissions equipped in automobiles are provided with torqueconverters which transmit engine torque via a lubricant to thetransmissions. The torque converters is so structured that the power cannot be transmitted if the difference in rotation between the input side(the engine side) and the output side (the transmission side) is notdeveloped. This rotation difference causes the transmission to bedecreased in power transmitting efficiency. With the background of theissues concerning environments, demands have been increasing forautomobiles which are fuel efficient for the purpose of reducing theamount of carbon dioxide gas discharged. In connection with this, thetransmissions are required to be more increased in power transmittingefficiency. Recently, as one of the measures, there have been usedtorque converters equipped with wet clutch hereinafter referred to as“torque converter clutch” which in addition to fluid coupling, transmitthe engine torque directly to the transmission mechanism variouslyaccording to the running conditions.

[0005] However, while the torque converter clutch is working, thecomfort on driving is greatly affected at the change of engine torque.Therefore, in the conventional mechanisms, the torque converter clutchis worked only at high road speeds at which the changes of the enginetorque are lessen, and is not worked at low road speeds. For thisreason, the transmission loss in the torque converters can not beavoided at low road speeds as well as at the time of starting and thusthe improvement of fuel economy as expected can not be achieved.

[0006] Recently, in order to reduce such a transmission loss, there hasbeen developed and introduced a so-called slipping controlling system inwhich the torque converter clutch works at low road speeds as well andabsorbs the vibration resulting from the change of engine torque, byrelative slippage of the clutch.

[0007] However, abnormal vibration, known as shudder, in the vehiclefrequently occurs at the torque converter clutch's friction surface whenthe slip-control of the clutch operates, and discomforts the drivingconditions. In order to prevent the shudder phenomenon, it is highlydemanded to provide a lubricant which has an excellent durability ofanti-shudder performance resulting from the improvement of frictioncoefficient (μ)-sliding velocity (V) characteristics so as to have afriction coefficient (μ) which increases as sliding velocity (V)increases.

[0008] The further improvement of anti-shudder durability has beendemanded because of the progressed enlargement of the low-speed range inwhich the slip-controlling mechanism operates.

[0009] The automatic transmissions and continuously variabletransmissions have wet clutches in their gear-change mechanism and frontand rear drive switching mechanism. If the friction property of suchclutches is poor, a transmission shock occurs at the change of speed,resulting in discomfort of driving. Therefore, a lubricant for automatictransmissions is required to have an excellent shifting property so asto decrease the shock occurring at the time of clutch engagement.

[0010] As one of the measures for improving the anti-shudder durabilityand shifting property of the lubricant, it has been proposed to blendtherewith large amounts of friction modifiers. However, depending on thetype of friction modifier, the addition thereof would extremely decreasethe friction coefficient of the wet clutch and fail to attain atransmission torque capacity.

[0011] The anti-shudder durability and shifting property and thetransmission torque capacity are in a trade-off relation. Therefore, itis desired to develop a lubricant composition having all of theseproperties.

[0012] With the background of the foregoing, the object of the presentinvention is to provide a novel lubricant composition which can retainan anti-shudder durability for extended periods and has a hightransmission torque capacity and improved shifting property.

BRIEF SUMMARY OF THE INVENTION

[0013] After intensive research efforts made to solve the foregoingproblems, it was found that the problems can be solved with a lubricantcomposition comprising a lubricant base oil blended with compoundsobtained by modifying specific succinimides.

[0014] That is, the present invention provides a lubricant compositionwhich comprises a lubricant base oil and one or more compounds selectedfrom the group consisting of those resulting from the modification ofsuccinimides represented by formula 1) or (2)

[0015] wherein R¹ and R² may be the same or different and are eachindependently a hydrocarbon group having 8 to 30 carbon atoms, R³ and R⁴may be the same or different and are each independently a hydrocarbongroup having 1 to 4 carbon atoms, R⁵ is hydrogen or a hydrocarbon grouphaving 1 to 30 carbon atoms, and n is an integer from 1 to 7.

[0016] R¹ and R² in formula (1) or (2) are preferably branchedhydrocarbon groups having 8 to 30 carbon atoms.

[0017] In formula (1) or (2), n is preferably an integer from 1 to 3.

[0018] The modified succinimide compounds are preferably those resultingfrom the modification of succinimides of formula (1) or (2) with one ormore compounds selected from the group consisting of boric acids,phosphoric acids, carboxylic acids, and derivatives thereof.

[0019] The lubricant composition further contains one or more frictionmodifiers and/or metal-based detergents.

[0020] The lubricant composition is preferably used in automatictransmissions and/or continuously variable transmissions.

[0021] The lubricant composition is preferably used in transmissionsequipped with a wet clutch and/or a wet break.

DETAILED DESCRIPTION OF THE INVENTION

[0022] The present invention will be described in more details below.

[0023] Lubricating base oils useful in this invention are any mineraloils and/or synthetic oils which are usually used as lubricant baseoils.

[0024] Specific examples of the mineral oils include paraffinic andnaphthenic mineral oils which are produced by subjecting lubricantfractions resulting from the atmospheric distillation and the vacuumdistillation of crude oil to one or more refining processes such assolvent deasphalting, solvent extraction, hydrocracking, solventdewaxing, catalytic dewaxing, hydro-refining, sulfuric acid washing, andclay treatment in suitable combination; and n-paraffins. Particularlypreferred are those improved in low-temperature flowability by dewaxingafter solvent- or hydro-refining. With the objective of improving lowtemperature flowability and oxidation stability of the resultingcomposition, it is preferred to use mineral oils of which %Cp specifiedby the n-d-m method of ASTM-D 3238-80 is 60 or greater and preferably 70or greater, %CA specified by the same is 10 or less and preferably 5 orless, and viscosity index is 95 or greater and preferably 100 orgreater.

[0025] Although not restricted, examples of synthetic oils are one ormore compounds selected from poly-α-olefins such as 1-octene oligomer,1-decene oligomer, and ethylene-propylene oligomer, and hydridesthereof; isobutene oligomers and hydrides thereof; isoparaffins;alkylbenzenes; alkylnaphthalenes; diesters such as ditridecyl glutarate,di-2-ethylhexyl adipate, diisodecyl adipate, ditridecyl adipate, anddi-2-ethylhexyl sebacate; polyol esters such as trimethylolpropanecaprylate, trimethylolpropane pelargonate, pentaerythritol-2-ethylhexanoate, and pentaerythritol pelargonate; polyoxyalkylene glycols;dialkyldiphenyl ethers; and polyphenyl ethers. When consideration isgiven to the solubility of additives, these synthetic oils arepreferably used in the form of mixtures thereof or mixtures with mineraloils rather than being used alone.

[0026] No particular limitation is imposed on the viscosity of thelubricant base oils. However, the kinematic viscosity at 100° C. of thelubricant base oil is preferably from 1 to 20 mm²/s, and more preferablyfrom 1.5 to 10 mm²/s.

[0027] The modified succinimide compounds hereinafter referred to asComponent (A) useful in the present invention are selected from thegroup consisting of compounds resulting from the modification ofsuccinimides represented by formula (1) or (2) below with boric acids,phosphorus acids, carboxylic acids, derivatives thereof, sulfuriccompounds, and triazoles:

[0028] In formula (1), R¹ and R² may be the same or different and areeach independently a straight-chain or branched hydrocarbon group having8 to 30 carbon atoms and preferably 12 to 25 carbon atoms. Examples ofsuch a hydrocarbon group are octyl, octenyl, nonyl, nonenyl, decyl,decenyl, dodecyl, dodecenyl, octadecyl, and octadecenyl groups andhydrocarbon groups having up to 30 carbon atoms. Hydrocarbon groupshaving less than 8 carbon atoms or exceeding 30 carbon atoms are notpreferred because they are not effective in improving the anti-shudderproperty. Preferred are branched hydrocarbon groups having 8 to 30carbon atoms, and particularly preferred are branched hydrocarbon groupshaving 10 to 25 carbon atoms. The use of a branched hydrocarbon grouphaving 8 to 30 carbon atoms is contributive to the production of alubricant composition having a higher torque capacity than the use ofstraight-chain hydrocarbon groups.

[0029] In formula (1) or (2), R³ and R⁴ may be the same or different andare each independently a hydrocarbon group having 1 to 4 carbon atoms,and preferably an alkylene group having 2 or 3 carbon atoms, such asethylene and propylene.

[0030] In formula (1) or (2), R⁵ is hydrogen or a straight-chain orbranched hydrocarbon group having 1 to 30 carbon atoms and preferably abranched hydrocarbon group having 8 to 30 carbon atoms and preferably 10to 25 carbon atoms.

[0031] In formula (1) or (2), n is an integer from 1 to 7, preferablyfrom 1 to 3, and particularly preferably 1. If n is an integer from 1 to3, the resulting lubricant composition has a higher torque capacity. Ifn is 1, the resulting composition has a more higher torque capacity.

[0032] Any suitable method may be employed for producing succinimidesrepresented by formula (1) or (2). For example, they can be obtained byreacting an alkyl or alkenyl anhydrous succinimide with a polyamine.More specifically, a bissuccinimide of formula (1) may be obtained byadding dropwise 1 mol of succinic anhydride having a straight-chain orbranched alkyl or alkenyl group to 0.5 mol of polyamine such asdiethylenetriamine, triethylenetetramine, and tetraethylenepentamineunder a nitrogen atmosphere at a temperature of 130 to 180° C. andpreferably 140 to 175° C. and then reacting the mixture for 1 to 10hours and preferably 2 to 6 hours, followed by removing the water thusformed. A monosuccinimide of formula (2) wherein R⁵ is hydrogen may beobtained by adding dropwise 1 mole of succinic anhydride as describedabove to 1 mole or more of polyamine as described above and reacting themixture under the same conditions, followed by distilling out theunreacted polyamine. A monosuccinimide of formula (2) wherein R⁵ is ahydrocarbon group having 1 to 30 carbon atoms may be obtained byreacting N-octadecyl-1,3-propanediamine with succinic anhydride asdescribed above under the same conditions as described above.

[0033] Boric acids and derivatives thereof used for modifyingsuccinimides represented by formula (1) or (2) are exemplified by boricacids, boric acid salts and borates. Specific examples of the boricacids are orthoboric acid, metaboric acid, and tetraboric acid. Specificexamples of the boric acid salts are alkaline metal salts, alkalineearth metal salts or ammonium salts of boric acid. More specificexamples are lithium borates such as lithium metaborate, lithiumtetraborate, lithium pentaborate, lithium perborate; sodium borates suchas sodium metaborate, sodium diborate, sodium tetraborate, sodiumpentaborate, sodium hexaborate, and sodium octaborate; potassium boratessuch as potassium metaborate, potassium tetraborate, potassiumpentaborate, potassium hexaborate, and potassium octaborate; calciumborates such as calcium metaborate, calcium diborate, tricalciumtetraborate, pentacalcium tetraborate, and calcium hexaborate; magnesiumborates such as magnesium metaborate, magnesium diborate, trimagnesiumtetraborate, pentamagnesium tetraborate, and magnesium hexaborate; andammonium borates such as ammonium metaborate, ammonium tetraborate,ammonium pentaborate, and ammonium octaborate. Borates may be esters ofboric acid with an alkyl alcohol having 1 to 6 carbon atoms. Specificexamples are monomethylborate, dimethylborate, trimethylborate,monoethylborate, diethylborate, triethylborate, monopropylborate,dipropylborate, tripropylborate, monobutylborate, dibutylborate, andtributylborate.

[0034] Specific examples of phosphoric acids and derivatives used formodifying succinimides represented by formula (1) or (2) areorthophosphoric acid, methaphosphoric acid, phosphorus acid,polyphosphoric acid, and compounds derived from the esterificationthereof.

[0035] Specific examples of carboxylic acids and derivatives used formodifying succinimides represented by formula (1) or (2) aremonocarboxylic acids having 1 to 30 carbon atoms, such as formic acid,acetic acid, glycolic acid, propionic acid, lactic acid, butyric acid,valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonicacid, capric acid, undecylic acid, lauric acid, tridecanoic acid,myristic acid, pentadecanoic acid, palmitic acid, margaric acid, stearicacid, oleic acid, nonadecanoic acid, and eicosanoic acid; polycarboxylicacids having 2 to 30 carbon atoms, such as oxalic acid, phthalic acid,trimellitic acid, and pyromellitic acid; anhydrides thereof; andesterified compounds thereof. Among these, preferred are carboxylicacids having 8 to 20 carbon atoms and derivatives thereof, andparticularly preferred are stearic acid and oleic acid.

[0036] Specific examples of sulfuric compounds used for modifyingsuccinimides represented by formula (1) or (2) aredialkyldithiophosphates, dialkenyldithiophosphates,dialkanoldithiophosphates, diaryldithiophosphates, and sulfonic acids.

[0037] Specific examples of triazoles used for modifying succinimidesrepresented by formula (1) or (2) are benzotriazole, tolyltriazole, andtetratriazole.

[0038] Although not restricted, Component (A) may be prepared byneutralizing or amidizing part or all of the amino groups and/or imidegroups because the reacting weight ratio of a compound represented byformula (1) or (2) to the above-described boric acids, phosphoric acids,carboxylic acids, derivatives thereof, or sulfuric compounds can bearbitrary adjusted.

[0039] More specifically, Compound (A) may be obtained by reacting 1 molof a compound represented by formula (1) or (2) with boric acids,phosphoric acids, carboxylic acids, derivatives thereof, or sulfuriccompounds in an amount of 0.4 m mol or more, preferably 0.6 m mole ormore and particularly preferably 0.9 n mol or more (n corresponds tothat of formula (1) or (2)), under a nitrogen atmosphere while heating.If the reaction ratio of boric acids, phosphoric acids, carboxylicacids, derivatives thereof, or sulfuric compounds to 1 mol of a compoundrepresented by formula (1) or (2) is 0.4 m mol or more, the resultinglubricant composition can be more enhanced in transmission torquecapacity. Whereas, if such a ratio is less than 0.4 m mol, theanti-shudder durability as sought by the present invention can not beattained.

[0040] One of more preferred examples of the production method ofComponent (A) is as follows. 1 mol of diethylenetriaminebisisooctadecenylsuccinimde and 1 mol of powdered boric acid are putinto a synthesizing vessel and reacted with stirring under a nitrogenatmosphere at a temperature of 80 to 150° C. and preferably 90 to 130°C. for 5 to 12 hours with separating the water thus produced until theunreacted powdery boric acid disappears. A solution of the reactionproduct diluted with toluene was filtered by pressure with a 1 μm Teflonfilter. The filtrate is put under vacuum conditions at a temperature of70 to 110° C. so as to remove the toluene thereby obtaining a compoundrepresented by formula (3) below:

[0041] Alternatively, a suitable amount of toluene is added to 1 mol ofdiethylenetriamine bisisooctadecenylsuccinimide in a synthesizing vesselunder a nitrogen atmosphere. 1 mol of phosphoric acid is added dropwiseto the mixture with stirring and reacted at room temperature to 100° C.for 2 to 10 hours, and preferably at room temperature for 1 to 5 hoursat the initial reaction stage and then at a temperature of 70 to 90° C.for 1 to 5 hours. The toluene is completely removed from the reactionproduct under vacuum conditions at a temperature of 70 to 130° C.thereby obtaining a compound represented by formula (4) below:

[0042] Further alternatively, a suitable amount of toluene is added to 1mol of diethylenetriamine bisisooctadecenylsuccinimide in a synthesizingvessel under a nitrogen atmosphere. A toluene solution of 1 mol of oleicacid is slowly added dropwise to the mixture with stirring and reactedat a temperature of 60 to 100° C. for 2 to 10 hours, and preferably at atemperature of 70 to 130° C. for 3 to 6 hours. The toluene is completelyremoved from the reaction product under vacuum conditions at atemperature of 70 to 130° C. thereby obtaining a compound represented byformula (5) below:

[0043] Although a method of producing Component (A) using oleic acid isdescribed above, Component (A) can be produced using lauric acid orstearic acid instead of oleic acid.

[0044] Component (A) may contain a mixture of a compound represented byformula (1) or (2), and boric acid, phosphoric acid, carboxylic acid,derivatives thereof or a sulfuric compound which are reacted by theabove-described methods.

[0045] Compounds resulting from the modification of a succinimide offormula (1) or (2) with one or more compounds selected fromboric acids,phosphoric acids, carboxylic acids, derivatives thereof, and sulfuriccompounds is used as Component (A) of the lubricant composition of thepresent invention. However, preferred for Component (A) are thoseresulting from the modification of a succinimide of formula (1) or (2)with a carboxylic acid having 10 to 25 carbon atoms, such as lauricacid, stearic acid and oleic acid with the objective of well-balancedtransmission torque capacity and speed-change property. It is preferredto use compounds resulting from the modification of bis-typesuccinimides of formula (1) than those resulting from the modificationof mono-type succinimides because the use of the former is contributiveto the production of a lubricant composition having a highertransmission torque capacity.

[0046] No particular limitation is imposed on the content of Component(A) in the lubricant composition of the present invention. However, thelower limit content is preferably 0.01 percent by mass, and morepreferably 0.1 percent by mass, while the upper limit content ispreferably 6 percent by mass, and more preferably 4 percent by mass,based on the total mass of the lubricant composition. The content ofComponent (A) in less than the lower limit is less effective inmaintaining an anti-shudder durability and an excellent speed-changeproperty, while the content of Component (A) in excess of the upperlimit fails to attain effects as expected.

[0047] In the present invention, a lubricant composition having anexcellent anti-shudder durability and an enhanced transmission torquecapacity can be obtained by blending a lubricant base oil with one ormore compounds selected from Components (A). However, friction modifierand/or metal-based detergents may be added to the composition alone orin combination. By blending these additives, the resulting lubricant canpossess a more excellent initial speed-change property while maintaininga transmission torque capacity and an anti-shudder durability.

[0048] Friction modifiers useful in the present invention may be anytype of those which are used for lubricants. Examples of such frictionmodifiers are amine compounds, fatty acid esters, fatty acid amides andfatty acid metallic salt, all having unmodified succinimides representedby formula (1) or (2) and alkyl or alkenyl groups having 6 to 30 carbonatoms, preferably straight-chain or branched alkyl or alkenyl groupshaving 6 to 30 carbon atoms.

[0049] Unmodified succinimides represented by formula (1) or (2) may becontained as an unreacted component in the resulting lubricantcomposition during the preparation of Component (A). The unreactedcomponent may be blended as a friction modifier. In this case, preferredare bis-type succinimides as represented by formula (1).

[0050] Eligible amine compounds are straight-chain or branched,preferably straight-chain monoamines having 6 to 30 carbon atoms;straight-chain or branched, preferably straight-chain polyamines having6 to 30 carbon atoms; alkylene oxide adducts thereof; salts of theseamine compounds and phosphates or phosphites; and products resultingfrom the modification of such salts with boric acids. Specific examplesare amine compounds such as lauryl amine, lauryl diethylamine, lauryldiethanolamine, dodecyldipropanolamine, palmitylamine, stearylamine,stearyltetraethylenepentamine, oleylamine, oleylpropylenediamine,oleyldiethanolamine, N-hydroxyethyloleylimidazolyne; alkylene oxideadducts of these amine compounds; salts of these amine compounds andphosphates such as di-2-ethylhexylphosphate or phosphites such as2-ethylhexylphosphite; boric acid-modified products of such salts; andmixtures thereof.

[0051] Eligible fatty acid esters are esters of straight-chain orbranched, preferably straight-chain fatty acids having 7 to 31 carbonatoms and aliphatic monohydric alcohols or aliphatic polyhydricalcohols. Specific examples are partial esters of glycerin such asglycerol monolaurate, glycerol monoisolaurate, glycerol dilaurate,glycerol diisolaurate, glycerol monomyristate, glycerolmonoisomyristate, glycerol dimyristate, glycerol diisomyristate,glycerol monopalmitate, glycerol monoisopalmitate, glycerol dipalmitate,glycerol diisopalmitate, glycerol monostearate, glycerolmonoisostearate, glycerol distearate, glycerol diisostearate, glycerolmonooleate, glycerol monoisooleate, glycerol dioleate, glyceroldiisooleate, glycerol monoisooleate, glycerol dioleate, and glycerolisooleate; partial esters of trimethylolethane such as trimethylolethanemonolaurate, trimethylolethane monoisolaurate, trimethylolethanedilaurate, trimethylolethane diisolaurate, trimethylolethanemonomyristate, trimethylolethane monoisomyristate, trimethylolethanedimyristate, trimethylolethane diisomyristate, trimethylolethanemonopalmitate, trimethylolethane monoisopalmitate, trimethylolethanedipalmitate, trimethylolethane diisopalmitate, trimethylolethanemonostearate, trimethylolethane monoisostearate, trimethylolethanedistearate, trimethylolethane diisostearate, trimethylolethanemonooleate, trimethylolethane monoisooleate, trimethylolethane dioleate,and trimethylolethane diisooleate; partial esters of trimethylolpropanesuch as trimethylolpropane monolaurate, trimethylolpropanemonoisolaurate, trimethylolpropane dilaurate, trimethylolpropanediisolaurate, trimethylolpropane monomyristate, trimethylolpropanemonoisomyristate, trimethylolpropane monopalmitate, trimethylolpropanemonoisopalmitate, trimethylolpropane dipalmitate, trimethylolpropanediisopalmitate, trimethylolpropane monostearate, trimethylolpropanemonoisostearate, trimethylolpropane diisostearate, trimethylolpropanemonooleate, trimethylolpropane monoisooleate, trimethylolpropanedioleate, and trimethylolpropane diisooleate; partial esters ofpentaerythritol such as pentaerythritol monolaurate, pentaerythritolmonoisolaurate, pentaerythritol dilaurate, pentaerythritol diisolaurate,pentaerythritol trilaurate, pentaerythritol triisolaurate,pentaerythritol monomyristate, pentaerythritol monoisomyristate,pentaerythritol dimyristate, pentaerythritol diisomyristate,pentaerythritol myristate, pentaerythritol triisomyristate,pentaerythritol monopalmitate, pentaerythritol monoisopalmitate,pentaerythritol dipalmitate, pentaerythritol diisopalmitate,pentaerythritol tripalmitate, pentaerythritol triisopalmitate,pentaerythritol monostearate, pentaerythritol monoisostearate,pentaerythritol distearate, pentaerythritol diisostearate,pentaerythritol tristearate, pentaerythritol triisostearate,pentaerythritol monooleate, pentaerythritol monoisooleate,pentaerythritol dioleate, pentaerythritol diisooleate, pentaerythritoltrioleate, and pentaerythritol triisooleate; partial esters of sorbitansuch as sorbitan monolaurate, sorbitan monoisolaurate, sorbitandilaurate, sorbitan diisolaurate, sorbitan trilaurate, sorbitantriisolaurate, sorbitan monomyristate, sorbitan monoisomyristate,sorbitan dimyristate, sorbitan diisomyristate, sorbitan trimyristate,sorbitan triisomyristate, sorbitan monopalmitate, sorbitanmonoisopalmitate, sorbitan dipalmitate, sorbitan diisopalmitate,sorbitan tripalmitate, sorbitan triisopalmitate, sorbitan monostearate,sorbitan monoisostearate, sorbitan distearate, sorbitan diisostearate,sorbitan tristearate, sorbitan triisostearate, sorbitan monooleate,sorbitan monoisooleate, sorbitan dioleate, sorbitan diisooleate,sorbitan trioleate, and sorbitan triisooleate; and mixtures thereof.

[0052] Eligible fatty acid amides are amides of straight-chain orbranched, preferably straight-chain fatty acids having 7 to 31 carbonatoms and aliphatic monoamines or aliphatic polyamines. Specificexamples are lauric acid amide, lauric acid diethanolamide, lauric acidmonopropanolamide, myristic acid amide, myristic acid diethanolamide,myristic acid monopropanolamide, palmitic acid amide, palmitic aciddiethanolamide, palmitic acid monopropanolamide, stearic acid amide,stearic acid diethanolamide, stearic acid monopropanolamide, oleic acidamide, oleic acid diethanolamide, oleic acid monopropanolamide, coconutoil fatty acid amide, coconut oil fatty acid diethanolamide, coconut oilfatty acid monopropanolamide, synthetic mixed fatty acid amide having 12or 13 carbon atoms, synthetic-mixed fatty acid diethanolamide having 12or 13 carbon atoms, synthetic-mixed fatty acid monopropanolamide having12 or 13 carbon atoms, and mixtures thereof.

[0053] Eligible fatty acid metallic salts are alkaline earth metal saltssuch as magnesium salt and calcium salt or zinc salt of straight-chainor branched, preferably straight-chain fatty acids having 7 to 31 carbonatoms. Specific examples are calcium laurate, calcium myristate, calciumpalmitate, calcium stearate, calcium oleate, coconut oil fatty acidcalcium, synthetic-mixed fatty acid calcium having 12 or 13 carbonatoms, zinc laurate, zinc myristate, zinc palmitate, zinc stearate, zincoleate, coconut oil fatty acid zinc, synthetic-mixed fatty acid zinchaving 12 or 13 carbon atoms, and mixtures thereof.

[0054] In the present invention, one or more compounds selected fromthese friction modifiers may be blended in suitable amounts. However,the content of the friction modifiers is usually within the range of0.01 to 5 percent by mass and preferably 0.03 to 3 percent by mass,based on the total mass of the lubricant composition.

[0055] Metal-based detergents useful in the present invention may be anycompounds which are usually used as detergents for lubricants.Sulfonates, phenates, salicylates and naphthenates of alkaline metals oralkaline earth metals may be used alone or in combination. The alkalinemetals may be sodium and potassium. The alkaline earth metals may becalcium and magnesium. Preferred metal-based detergents are sulfonates,phenates, salicylates of calcium or magnesium. These metal-baseddetergents have a total base number of 0 to 500 mgKOH/g. Thesemetal-based detergents are blended in an amount of 0.001 to 0.5 percentby mass of alkaline metal or alkaline earth metal, based on the totalmass of the lubricant composition. In order to avoid the decrease offriction coefficient due to the clogging of the friction material of awet clutch, the upper limit content of the friction modifiers is 0.1percent by mass and preferably 0.05 percent by mass or less.

[0056] In order to further enhance the capabilities of the lubricantcomposition of the present invention, it may be blended with knownlubricant additives such as ashless dispersants, viscosity indeximprovers, phosphorus-based additives, extreme pressure additives,oxidation inhibitors, corrosion inhibitors, anti-foaming agents anddyes. These additives may be added alone or in combination.

[0057] Ashless dispersants useful in the present invention may be anycompounds which are used as ashless dispersants for lubricants, such asnitrogen-containing compounds having in their molecule at least onealkyl or alkenyl group having 40 to 400, preferably 60 to 350 carbonatoms; bis or mono type succinimides having alkenyl groups having 40 to400, preferably 60 to 350 carbon atoms; products obtained by modifyingthese compounds with the above-described boric acids, phosphorus acids,carboxylic acids, derivatives thereof, or sulfuric compounds. One ormore of these compounds may be used alone or in combination. The alkylor alkenyl group may be straight-chain or branched and may be a branchedalkyl or alkenyl group derived from oligomers such as propylene,1-butene and isobutylene or cooligomers of ethylene and propylene.Preferred are polybutenyl groups obtained by polymerizing butenemixtures or highly purified isobutylene using an aluminum-based catalystor a boron fluoride-based catalyst. Particularly preferred are thoseobtained by removing the halogen compounds from the polybutenyl groups.Alkyl or alkenyl groups having less than 40 carbon atoms are notpreferred because the resulting composition becomes poor in a detergentdispersing property, while those having more than 400 carbon atoms arenot preferred because the resulting composition may be deteriorated inlow-temperature flowability. Although not restricted, the content ofthese compounds in the lubricant composition of the present invention isfrom 0.1 to 10 percent by mass, preferably 1 to 8 percent by mass, basedon the total mass of the composition. With the objective of the furtherenhancement of a speed-change property, ashless dispersants useful inthe present invention are succinimides having a weight-average molecularweight of 700 to 3,500, preferably 900 to 2,000 and/or those modifiedwith boric acid.

[0058] With the objective of the enhancement of the ability to avoid thepeel-off of the clutch, the ashless dispersants are blended withpreferably a boric acid-modified succinimide, more preferably two ormore boric acid-modified succinimides. viscosity index improvers usefulin the present invention may be non-dispersion-type viscosity indeximprovers such as copolymers of one or more monomers selected fromvarious types of methacrylates or hydrides of such copolymers anddispersion-type viscosity index improvers such as those obtained bycopolymerizing various types of methacrylates containing a nitrogencompound. Specific examples of another types of viscosity index improverare non-dispersion type- and dispersion type-ethylene-α-olefincopolymers, of which α-olefin may be propylene, 1-butene and 1-pentene,hydrides thereof, polyisobutylenes, hydrides thereof, styrene-dienehydrogenated copolymers, styrene-maleic anhydride ester copolymers andpolyalkylstyrenes.

[0059] It is necessary to select the molecular weight of the viscosityindex improver in view of shear stability. Specifically, the molecularweight of the dispersion type- and non-dispersion type-polymethacrylatesshould be within the range of 5,000 to 150,000, preferably 5,000 to35,000, and the molecular weight of the polyisobutylenes and hydridesthereof should be within the range of 800 to 5,000, preferably 1,000 to4,000. The molecular weight of the polyisobutylene and hydrides thereofshould be 800 to 5,000, preferably 1,000 to 4,000. When using theethylene-α-olefin copolymers and hydrides thereof, it is preferred touse those of 800 to 150,000, preferably 3,000 to 12,000 in molecularweight.

[0060] Among these viscosity index improvers, the ethylene-α-olefincopolymers and hydrides thereof are particularly contributive to theproduction of a lubricant composition which has an excellent shearstability.

[0061] One or more of the above-described viscosity index improvers maybe added in a suitable amount to the inventive lubricant composition.The viscosity index improver may be added in an amount of 0.1 to 40.0percent by mass, based on the total mass of the composition.

[0062] Phosphorus-containing additives useful in the present inventionmay be any phosphorus compounds which are usually used asphosphorus-containing additives for lubricants, such asalkyldithiophosphates, zinc alkyldithiophosphates, monophosphates,diphosphates, triphosphates, monophosphites, diphosphites,triphosphites, and salts of these esters and amines or alkanolamines.

[0063] Although not restricted, the content of the phosphorus-containingadditives is preferably 0.005 to 0.2 percent by mass of phosphorus,based on the total mass of the lubricant. The content less than 0.005percent by mass of phosphorus would be poor in an anti-wear property,while the content in excess of 0.2 percent by mass of phosphorus wouldresult in the deterioration of oxidation stability.

[0064] Extreme pressure additives useful in the present invention may beany compounds which are usually used as extreme pressure additives forlubricants. Extreme pressure additives may be sulfur-containingcompounds such as disulfides, olefin sulfides and sulfurized fats andoils. One or more of these compounds is preferably added in an amount of0.01 to 5.0 percent by mass based on the total mass of the lubricant.

[0065] Oxidation inhibitors useful in the present invention arephenol-based or amine-based compounds which may be alkylphenols such as2-6-di-tert-butyl-4-methylphenol, bisphenols such asmethylene-4,4-bisphenol(2,6-di-tert-butyl-4-methylphenol);naphthylamines such as phenyl-α-naphthylamine and dialkyldiphenylamines;zinc dialkyldithiophosphates such as zincdi-2-ethylhexyldithiophosphate; and esters of3,5-di-tert-butyl-4-hydroxyphenyl fatty acid (propionic acid) with amono- or poly-hydric alcohol such as methanol, octadecanol,1,6-hexanediol, neopentyl glycol, thiodiethylene glycol, triethyleneglycol or pentaerythritol.

[0066] One or more of these oxidation inhibitors may be added insuitable amounts. However, the content of the oxidation inhibitor ispreferably within the range of 0.01 to 5.0 percent by mass, based on thetotal mass of the lubricant.

[0067] Corrosion inhibitors useful in the present invention may be anycompounds which are usually used as corrosion inhibitors for lubricants,such as benzotriazoles, tolyltriazoles, thiadiazoles and imidazoles. Oneor more of these compounds is preferably added in an amount of 0.01 to3.0 percent by mass, based on the total mass of the lubricant.

[0068] Anti-foaming agents useful in the present invention may be anycompounds which are usually used as anti-foaming agents for lubricants,which may be silicones, such as dimethylsilicone and fluorosilicone. Oneor more of these compounds is preferably added in an amount of 0.001 to0.05 percent by mass, based on the composition.

[0069] Any types of dye may be added generally in an amount of 0.001 to1.0 percent by mass, based on the total mass of the composition.

[0070] Examples of the present invention will now be provided, with theunderstanding that the invention is in no way limited by these examples.

EXAMPLES 1 TO 14

[0071] and

Comparative Examples 1 to 4

[0072] Lubricant compositions (Inventive Examples 1 to 14) for automatictransmissions according to the present invention are prepared inaccordance with the formulations shown in Table 1. The followinganti-shudder durability test and speed-change clutch friction propertytest were conducted for each of the compositions so as to evaluate theanti-shudder durability, speed-change property for a speed-changeclutch, and transmission torque capacity. The results are shown in Table1.

[0073] For comparison, lubricant compositions of Comparative Examples 1to 4 were also prepared in accordance with the formulations shown inTable 2 and the same evaluation tests were conducted therefor. Theresults are shown in Table 2.

[0074] [Anti-shudder Durability Test]

[0075] A low-speed slipping test was conducted based on “Test method foranti-shudder performance of automatic transmission fluids” prescribed inJASO M349-98 where an oil temperature was changed from 120° C. to 140°C. The evaluation of anti-shudder durability was indicated by a ratio ofthe durability of the oil usually used in the above test method, as acriterion to those of Inventive and Comparative Examples.

[0076] The measurement was conducted at intervals of 0, 6, 12, and 24hours and thereafter at intervals of 24 hours.

[0077] A lubricant composition is considered to have a good anti-shudderdurability when the durability exceeds that of the criterion oil, thatis, 72 hours. The test was terminated when the durability is 4 timesgreater than that of the criterion oil, that is, exceeds 288 hours.

[0078] [Speed-change Clutch Friction Property Test]

[0079] SAE No. 2 test was conducted in accordance with “Test method forfriction property of automatic transmission fluids” prescribed in JASOM348-95. The resulting μs and μO/μd were used as indexes of transmissiontorque capacity and shifting property, respectively. TABLE 1 InventiveExamples 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Refined mineral oil ¹⁾ mass %86.697 86.697 86.697 86.697 86.697 86.697 86.697 86.697 86.697 86.69786.697 86.597 86.597 86.497 Oleic acid-modified compound ²⁾ mass % 3 — —— — — — — — — — — — — Boric acid-modified compound ³⁾ mass % — 3 — — — —— — — — — — — — Phosphoric acid-modified compound ⁴⁾ mass % — — 3 — — —— — — — — — — Lauric acid-modified compound ⁵⁾ mass % — — — 3 — — — — —— — 3 3 3 Lauric acid-modified compound ⁶⁾ mass % — — — — 3 — — — — — —— — — Oleic acid-modified compound ⁷⁾ mass % — — — — — 3 — — — — — — — —Stearic acid-modified compound ⁸⁾ mass % — — — — — — 3 — — — — — — —Oleic acid-modified compound ⁹⁾ mass % — — — — — — — 3 — — — — — — Oleicacid-modified compound ¹⁰⁾ mass % — — — — — — — — 3 — — — — — Oleicacid-modified compound ¹¹⁾ mass % — — — — — — — — — 3 — — — — Oleicacid-modified compound ¹²⁾ mass % — — — — — — — — — 3 — — — SuccinimideA ¹³⁾ mass % — — — — — — — — — — — — — — Succinimide B ¹⁴⁾ mass % — — —— — — — — — — — — — — Succinimide C ¹⁵⁾ mass % — — — — — — — — — — — — —— Friction modifier A ¹⁶⁾ mass % — — — — — — — — — — — 0.1 — — Frictionmodifier B ¹⁷⁾ mass % — — — — — — — — — — — — 0.1 — Metal-baseddetergent ¹⁸⁾ mass % — — — — — — — — — — — — — 0.2 Ashless dispersant¹⁹⁾ mass % 3 3 3 3 3 3 3 3 3 3 3 3 3 3 Boron-modified ashless dispersant²⁰⁾ mass % 1 1 1 1 1 1 1 1 1 1 1 1 1 1 Viscosity index improver ²¹⁾ mass% 5 5 5 5 5 5 5 5 5 5 5 5 5 5 Anti-wear agent ²²⁾ mass % 0.2 0.2 0.2 0.20.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Oxidation inhibitor A ²³⁾ mass %0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Oxidationinhibitor B ²⁴⁾ mass % 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.50.5 0.5 Corrosion inhibitor ²⁵⁾ mass % 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.10.1 0.1 0.1 0.1 0.1 0.1 Anti-foaming agent ²⁶⁾ mass % 0.003 0.003 0.0030.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003Transmission torque capacity SAE No.2 μs (2000 cycles) 0.110 0.140 0.1360.145 0.149 0.140 0.139 0.114 0.111 0.108 0.110 0.140 0.137 0.139Shifting property SAE No.2 μ0/μd (100 cycles) 0.97 1.02 1.02 1.01 1.020.99 0.98 0.97 0.88 0.94 0.94 0.97 0.98 0.98 Anti-shudder durability(Comparison with criterion oil) >4 >4 >4 >4 >4 >4 >4 >4 >4 >4 >4 >4 >4>4

[0080]1) hydro-refined mineral oil (kinematic viscosity at 100° C.: 4mm²/s, viscosity index: 120)

[0081] 2) reaction product of diethylenetriaminebis(n-octadecenyl)succinimide/oleic acid (molar ratio=1/1)

[0082] 3) reaction product of diethylenetriaminebis(iso-octadecenyl)succinimide/boric acid (molar ratio=1/1)

[0083] 4) reaction product of diethylenetriaminebis(iso-octadecenyl)succinimide/phosphoric acid (molar ratio=1/1)

[0084] 5) reaction product of diethylenetriaminebis(iso-octadecenyl)succinimide/lauric acid (molar ratio=1/1)

[0085] 6) reaction product of diethylenetriaminebis(iso-octadecenyl)succinimide/lauric acid (molar ratio=1/0.5)

[0086] 7) reaction product of diethylenetriaminebis(iso-octadecenyl)succinimide/oleic acid (molar ratio=1/1)

[0087] 8) reaction product of diethylenetriaminebis(iso-octadecenyl)succinimide/stearic acid (molar ratio=1/1)

[0088] 9) reaction product of triethylenetetraminebis(iso-octadecenyl)succinimide/oleic acid (molar ratio=1/2)

[0089] 10) reaction product of tetraethylenepentaminebis(iso-octadecenyl)succinimide/oleic acid (molar ratio=1/3)

[0090] 11) reaction product of pentaethylenehexaminebis(iso-octadecenyl)succinimide/oleic acid (molar ratio=1/4)

[0091] 12) reaction product of diethylenetriaminemono(iso-octadecenyl)succinimide/oleic acid (molar ratio=1/2)

[0092] 13) diethylenetriamine bis(n-octadecenyl)succinimide

[0093] 14) diethylenetriamine bis(iso-octadecenyl)succinimide

[0094] 15) diethylenetriamine mono(iso-octadecenyl)succinimide

[0095] 16) ethoxylated isostearylamine

[0096] 17) condensation product of isostearic acid andtetraethylenepentamine

[0097] 18) calcium sulfonate (total base number: 300 mgKOH/g, calciumcontent: 12 mass %)

[0098] 19) polybutenylsuccinimide (bis type, the weight-averagemolecular weight of the polybutenyl group: 1,000)

[0099] 20) boric acid-modified polybutenylsuccinimide (bis type, boroncontent: 0.5 mass %, the weight-average molecular weight of thepolybutenyl group: 1,300)

[0100] 21) dispersion type polymethacrylate (weight-average molecularweight: 120,000)

[0101] 22) arylphosphite

[0102] 23) dialkyldiphenylamine-based oxidation inhibitor

[0103] 24) bisphenol-based oxidation inhibitor

[0104] 25) tolyltriazole

[0105] 26) dimethylsilicone TABLE 2 Comparative Examples 1 2 3 4 Refinedmineral oil¹⁾ mass % 89.697 86.697 86.697 86.697 Oleic acid-modifiedmass % — — — — compound²⁾ Boric acid-modified mass % — — — — compound³⁾Phosphoric acid-modified mass % — — — — compound⁴⁾ Lauric acid-modifiedmass % — — — — compound⁵⁾ Lauric acid-modified mass % — — — — compound⁶⁾Oleic acid-modified mass % — — — — compound⁷⁾ Stearic acid-modified mass% — — — — compound⁸⁾ Oleic acid-modified mass % — — — — compound⁹⁾ Oleicacid-modified mass % — — — — compound¹⁰⁾ Oleic acid-modified mass % — —— — compound¹¹⁾ Oleic acid-modified mass % — — — — compound¹²⁾Succinimide A¹³⁾ mass % — 3 — — Succinimide B¹⁴⁾ mass % — — 3 —Succinimide C¹⁵⁾ mass % — — — 3 Friction modifier A¹⁶⁾ mass % — — — —Friction modifier B¹⁷⁾ mass % — — — — Metal-based detergent¹⁸⁾ mass % —— — — Ashless dispersant¹⁹⁾ mass % 3 3 3 3 Boron-modified ashless mass %1 1 1 1 dispersant²⁰⁾ Viscosity index mass % 5 5 5 5 improver²¹⁾Anti-wear agent²²⁾ mass % 0.2 0.2 0.2 0.2 Oxidation inhibitor A²³⁾ mass% 0.5 0.5 0.5 0.5 Oxidation inhibitor B²⁴⁾ mass % 0.5 0.5 0.5 0.5Corrosion inhibitor²⁵⁾ mass % 0.1 0.1 0.1 0.1 Anti-foaming agent²⁶⁾ mass% 0.003 0.003 0.003 0.003 Transmission torque 0.174 0.109 0.153 0.110capacity SAE No. 2 μs (2000 cycles) Shifting property 1.05 0.97 1.030.96 SAE No. 2 μO/μd (100 cycles) Anti-shudder durability 0.1 3.3 2.03.3 (Comparison with criterion oil)

[0106] 1) hydro-refined mineral oil (kinematic viscosity at 100° C.: 4mm²/s, viscosity index: 120)

[0107] 2) reaction product of diethylenetriaminebis(n-octadecenyl)succinimide/oleic acid (molar ratio=1/1)

[0108] 3) reaction product of diethylenetriaminebis(iso-octadecenyl)succinimide/boric acid (molar ratio=1/1)

[0109] 4) reaction product of diethylenetriaminebis(iso-octadecenyl)succinimide/phosphoric acid (molar ratio=1/1)

[0110] 5) reaction product of diethylenetriaminebis(iso-octadecenyl)succinimide/lauric acid (molar ratio=1/1)

[0111] 6) reaction product of diethylenetriaminebis(iso-octadecenyl)succinimide/lauric acid (molar ratio=1/0.5)

[0112] 7) reaction product of diethylenetriaminebis(iso-octadecenyl)succinimide/oleic acid (molar ratio=1/1)

[0113] 8) reaction product of diethylenetriaminebis(iso-octadecenyl)succinimide/stearic acid (molar ratio=1/1)

[0114] 9) reaction product of triethylenetetraminebis(iso-octadecenyl)succinimide/oleic acid (molar ratio=1/2)

[0115] 10) reaction product of tetraethylenepentaminebis(iso-octadecenyl)succinimide/oleic acid (molar ratio=1/3) 11)reaction product of pentaethylenehexaminebis(iso-octadecenyl)succinimide/oleic acid (molar ratio=1/4) 12)reaction product of diethylenetriaminemono(iso-octadecenyl)succinimide/oleic acid (molar ratio=1/2) 13)diethylenetriamine bis(n-octadecenyl)succin imide

[0116] 14) diethylenetriamine bis(iso-octadecenyl)succinimide

[0117] 15) diethylenetriamine mono(iso-octadecenyl)succinimide

[0118] 16) ethoxylated isostearylamine

[0119] 17) condensation product of isostearic acid andtetraethylenepentamine

[0120] 18) calcium sulfonate (total base number: 300 mgKoH/g, calciumcontent 12 mass %)

[0121] 19) polybutenylsuccinimide (bis type, the weight-averagemolecular weight of the polybutenyl group: 1,000)

[0122] 20) boric acid-modified polybutenylsuccinimide (bis type, boroncontent: 0.5 mass %, the weight-average molecular weight of thepolybutenyl group: 1,300)

[0123] 21) dispersion type polymethacrylate (weight-average molecularweight: 120,000)

[0124] 22) arylphosphite

[0125] 23) dialkyldiphenylamine-based oxidation inhibitor

[0126] 24) bisphenol-based oxidation inhibitor

[0127] 25) tolyltriazole

[0128] 26) dimethylsilicone

[0129] As apparent from the results shown in Tables 1 and 2, thelubricant compositions of Inventive Examples 1 to 14 had an enhancedtransmission capacity, an excellent speed-change property, and along-lasting anti-shudder durability.

[0130] In contrast, the composition of Comparative Example 1 which isfree of an acid-modified succinimide compound had a poor shiftingproperty and a short anti-shudder durability. The compositions ofComparative Examples 2 to 4 containing a non-acid-modified succinimidewere poor in anti-shudder durability.

[0131] As described above, the lubricant composition of the presentinvention has an anti-shudder property for a prolonged period, anenhanced transmission torque capacity, and an excellent shiftingproperty. However, the composition can be used as lubricants not onlyfor automatic transmissions and/or continuously variable transmissionsbut also construction or agricultural machines equipped with a wetclutch and/or wet brake, manual transmissions, motorcycle gasolineengines, automobile gasoline engines, diesel engines, gas engines andshock absorbers.

What is claimed is:
 1. A lubricant composition which comprises alubricant base oil and one or more compounds resulting from themodification of a succinimide represented by formula (1) or (2)

wherein R¹ and R² are the same or different and are each independently ahydrocarbon group having 8 to 30 carbon atoms, R³ and R⁴ are the same ordifferent and are each independently a hydrocarbon group having 1 to 4carbon atoms, R⁵ is hydrogen or a hydrocarbon group having 1 to 30carbon atoms, n is an integer from 1 to
 7. 2. The lubricant compositionaccording to claim 1 wherein said R¹ and R² are each independently abranched hydrocarbon having 8 to 30 carbon atoms.
 3. The lubricantcomposition according to claim 1 wherein said n is an integer from 1 to3.
 4. The lubricant composition according to claim 1 wherein saidmodified succinimide compound results is a compound modified with one ormore compounds selected from the group consisting of boric acids,phosphoric acids, carboxylic acids, and derivatives thereof.
 5. Thelubricant composition according to claim 1 which further comprises oneor more additives selected from the group consisting of frictionmodifiers and metal-based detergents.
 6. The lubricant compositionaccording to claim 1 wherein said composition is used for automatictransmissions and/or continuously variable transmissions.
 7. Thelubricant composition according to claim 1 wherein said composition isused for transmissions having wet clutches and/or wet brakes.